Propylene polymers are thermoplastic and hence can be melted by heating and molded to give articles having various shapes. Therefore, the propylene polymers are widely employed for producing outer housings of household electric appliances such as refrigerators and washing machines and various molded products such as trays, shelf plates, wrapping films. It is known that the propylene polymers are mixed with additives such as inorganic fillers, nucleating agents and elastomers so as to improve rigidity and impact strength of the molded products. As the inorganic fillers, there are known fibrous inorganic fillers such as fibrous basic magnesium sulfate and non-fibrous fillers such as talc. Basic magnesium sulfate has the chemical formula of MgSO4.5Mg(OH)2.3H2O.
JP 8-134321A describes a molded propylene polymer product comprising crystalline propylene polymer, specific elastomer, talc, fibrous basic magnesium sulfate (fibrous magnesium oxysulfate) and a nucleating agent. This publication teaches that a molded product comprising crystalline propylene polymer, elastomer, talc, fibrous basic magnesium sulfate and a nucleating agent (Example 2) shows higher modulus in flexure than a molded product comprising crystalline propylene polymer, elastomer, talc and fibrous basic magnesium sulfate (Comparison Example 3), which in turn shows higher modulus in flexure than a molded product comprising crystalline propylene polymer, elastomer and talc (Comparison Example 2). This publication further describes that the propylene polymer products can be produced by injection molding performed after dry-blending of the components or after melt-kneading of the components.
As is taught in JP 8-134321A, a molded product comprising propylene polymer, fibrous basic magnesium sulfate and a nucleating agent shows a higher modulus in flexure than a molded propylene polymer product comprising no additives. In certain uses of molded propylene polymer products, however, it is required to increase the modulus in flexure of these products. Otherwise, in certain uses of molded propylene polymer products, it is required for the molded propylene polymer products to have high physical properties other than the modulus in flexure. For instance, the molded propylene polymer products employed as the outer housings of household electric appliances, trays or shelf plates should have high flexural strength and high resistance to deformation under heating. As for wrapping sheets, it is required that the wrapping sheets show high tensile yield strength so that the thin wrapping sheet shows high resistance to deformation under high tensile conditions.